Method of preventing measling when making epoxy laminates

Abstract

Abstract Measling, the appearance of spots or stars under the surface of a resin portion of an epoxy-glass fiber laminate, is prevented or significantly diminished by a laminating process which includes curing plies of glass cloth and epoxy resin at an elevated temperature, e.g., 300* to 400* F., at an elevated pressure, e.g., 750 to 1,500 pounds per square inch, until gel formation occurs by reaction of the epoxy resin and curing agent, after which heating is continued at approximately the same temperature but at a lower pressure, e.g., 50 to 400 lbs./sq. in. Suitably, the initial curing step lasts for about 30 to 80 minutes and the subsequent step takes about 20 to 50 minutes, such times varying with the thickness of the laminate, the nature of the expoxy resin, the temperature employed, the geometry of the laminate, the type of reinforcing cloth, the curing apparatus used and the presence or absence of metal molded into the plastic. After completion of heating, the laminate is cooled in the press and is then removed.

Inventors

• 👤 Michael Riccitiello
• 👤 Harry A Kreitmayer

Bibliographic Details